During the review, we determined that it would be good for the value indicator to stretch when the text scale was smaller, and the shrink when it was larger, to keep the value visible over the finger at small sizes, and closer to the finger at large sizes. This implements that change.
* Roll engine to b6df7a637498ca9beda1fa9cd7210e3202ea599f.
Changes since last roll:
```
b6df7a637 Roll dart to 290c576264faa096a0b3206c71b2435309d9f904. (#4771)
a6764dbd5 Add sources for Fuchsia target. (#4763)
2d5900615 [fuchsia] Remove unused header file. (#4769)
9717063b7 Revert "Roll dart to c080951d45e79cd25df98036c4be835b284a269c. (#4767)" (#4768)
9a9814312 Roll dart to c080951d45e79cd25df98036c4be835b284a269c. (#4767)
e74e8b35c [async] Update includes of async headers to new path (#4760)
e2c4b2760 Use Dart 2 camel case constants in the engine Dart libraries (#4766)
9c1e48434 Updates for Fuchsia roll. (#4765)
14c940e27 Switch from fxl::Mutex to std::mutex (#4764)
debf82c0b Roll Garnet (#4759)
5bffdefbb Use weak pointers to the accesibility bridge from objects vended to the UIKit accessibility framework. (#4761)
```
Fixed the real repaint problem the Slider had (missing addListener), and added tests for it.
Added GlobalKey reparenting test.
Added the ability for the value indicator to slide left and right to avoid falling off the edge of the screen.
It only shifts as much as it can without deforming, but even at large text scales, that is enough to keep the text on the screen.
Updated the formatting on theme_data.dart and others to use longer line length.
Also, removed a color tween that faded the value indicator in as it scaled, since that wasn't to spec.
* Update dependencies with forced upgrade.
Now that https://github.com/flutter/flutter/issues/15261 is fixed, do the update with upgrade.
* Update test package use following upgrade
* Replace addOption(allowMultiple) with addMultiOption
* add fromSpan constructor to Text widget and simple smoke test:
* change fromSpan to rich, clean up comments
* 'directly from' to 'with'
* make sure text styles are applied to either data or textspan. add diagnostic properties for span
* add expectation for text style to test case
* some work on diagnostics and docs
Make flutter test support the --track-widget-creation flag.
Add widget creation location tests. Tests are skipped when
--track-widget-creation flag is not passed.
* RenderWrap.performLayout takes should take spacing into consideration when deciding to move to next row/axis
* fix spacing in text
* remove dart:developer import
* remove extra line
* add a debug check that the returned Type of State.initState and State.didUpdateWidget are not Futures
* add test to verify that async lifecycles throw FlutterErrors
* address some feedback, match implementation of setState check
* address feedback from hixie
* fix odd spacing in test
Orientation, and by extension time for rotation between orientations,
was aspirational and never used.
While this is technically a breaking change, this code never actually
did anything. If you were setting either orientation or timeForRotation,
simply delete those parameters and the code will continue to behave
identically to how it had been.
Fixes a small rendering problem when dragging the slider, as well as a couple of small bugs (de-duping of value changes, and actually using a parameter passed to _unlerp).
This implements an update to the look of the Slider widget.
Specifically, it does the following:
* Adds the ability to customize the colors of all components of the slider
* Adds the ability to customize the shape of the slider thumb and value indicator
* Adds the ability to show the value indicator on continuous sliders
* Updates the default value indicator to be a "paddle" shape with new animations.
* Changes the tick marks to be visible all the time on discrete sliders
* Fixes a memory leak of an animation controller.
* Removes "thumbOpenAtMin" flag, which is no longer needed, and can be emulated by the
custom thumb shape support. It was not widely used.
* Adds tests for all of the new features.
